Slurry-blasting apparatus



Sept. 17, 1963 Filed Sept. 25, 1959 C. E-. NOLAN SLURRY-BLASTING APPARATUS 2 Sheets-Sheet l INVENTOR. was Nam/v 1114. Jahui 4 a Sept. 17, 1963 Filed Sept. 25, 1959 C- E- NOLAN SLURRY-BLASTING APPARATUS 2 Sheets-Sheet 2 IN V EN TOR.

CLAUDE f. Nam/v BY M United States Patent 3,103,765 SLURRY-BLASTTNG APPARATUS Claude E. Nolan, Bridgeton, N.J., assignor to Owens- Illinois Glass Company, a corporation of Ohio Filed Sept. 25, 1959, Ser- No. 842,264 13 Claims. (Cl. 518) The present invention relates to an improved slurry surface finishing and treating apparatus, and more particularly to improved apparatus wherein the surface finishing is accomplished by utilizing a powerful stream of fluid borne abrasive material in slurry form.

Among other important objects, it is a principal object of the present invention to provide improved apparatus employing an abrasive slurry of the aforementioned type for producing a surface finish of extreme smoothness on articles subjected to such slurry.

Another object of this invention is to provide apparatus capable of accomplishing the surfacing operation and the subsequent cleaning and corrosion inhibiting operations in an economical manner and in such a manner as to substantially reduce the waste and loss of abrasive slurry and treating mediums utilized.

A further object of the present invention is to provide apparatus for accomplishing such slurry blasting and surface cleaning and treating at one convenient location whereby the entire surface finishing operation can be effected rapidly and with a minimum of movement of the articles being resurfaced and finished.

A still further object of this invention is to provide apparatus for maintaining the fluid borne abrasive in thoroughly agitated and homogeneously suspended condition with its fluid carrier during the surfacing operation.

A still further objective is to provide improved apparatus for removing and reusing the residual s'lurrious abrasive remaining on the slurry-blasted article or workpiece subsequent to the slurry blasting operation.

A still further objective is to provide apparatus for treating the slurry-blasted surfaces of the workpiece with a corrosion inhibiting medium immediately following the slurry blasting and washing operations and to recapture the medium for reuse.

Another particular object of the present invention is to exhaust the slurry blasting chamber during the slurry blasting operation to remove the vapors and hue air-borne abrasive material from within the chamber and return such vapors and abrasive material to the main slurry supply.

A more specific object of this invention is to provide a carrier for easy movement of the workpieces into the blasting chamber through an access opening therein and to further construct the carrier in such manner that it will also serve as a door to close the access opening when the workpieces are positioned within the blasting chamber.

Other objects and advantages will become apparent from the following detailed description taken in conjunction with the accompanying drawings upon which a preferred embodiment of the apparatus selected for performing the present invention is illustrated, and wherein:

FIG. 1 is a schematic front perspective view of apparatus embodying the present invention; and including a cabinet enclosure for the slurry blasting operation and adjacent washing and surface treating stations; and

FIG. 2 is a vertical sectional view along the plane I l-4i in FIG. 1 and taken through the viewing window in the cabinet enclosure; and

FIG. 3 is a fragmentary vertical sectional view of i 31fi 3,7 Patented Sept. 17, 1963 Generally, the invention is shown embodied in apparatus commonly referred to as Wet blasting or slurry blasting apparatus in cooperative association with washing and surface treating apparatus, the latter effecting a washing and treating of the workpiece after it has been subjected to the blasting operation. Referring particularly to FIG. 1, the blasting operation is carried out within a cabinet enclosure 10. Thereafter, the workpiece is transferred to a washing station designated as A and which is located adjacent to the cabinet enclosure 10. Following the washing operation the workpiece is removed to a treating station designated as B and situated adjacent to washing station A. The movement of the workpiece or group of workpieces between the stations A and B and the cabinet enclosure 10 is conveniently accomplished by means of a wheeled dolly 11 which rides on tracks 12 running between stations A and B and into the interior of the cabinet enclosure 10 through an access opening in the side wall thereof adjacent to station A. Hence, the workpiece or group of workpieces may be placed on the bed of the dolly 11 and wheeled thereon into the cabinet enclosure 1d wherein the blasting operation is performed to remove scale, rust, dirt etc. from the surfaces of the workpiece. Thereafter, the dolly 11 may be withdrawn from the cabinet enclosure 1t and wheeled along tracks 12 to station A where the workpiece is thoroughly washed and rinsed to remove foreign material adhering to the polished surfaces thereof including residual slurry and abrasive material remaining thereon from the wet blast operation. Following a thorough washing, the dolly '11 is wheeled to station B where the washed workpieces are preferablytre-ated with a corrosion inhibiting medium in order to protect the newly polished and exposed surfaces thereof.

A preferred form of construction of the cabinet enclosure ld is illustrated in FIG. 1, the illustrated enclosure being of a type well-known in the art and comprising a hollow interior blasting chamber 13 emptying into a hopper 14 at the base of the enclosure; a viewing window 15 formed in the front wall of the cabinet enclosure which permits the operator to view the blasting operation; and arm openings 16 formed in the front Wall of the enclosure which provide access into flexible waterproof sleeves 17 extending into the blasting chamber and having gloves 18 on the inner extremities thereof which permit the operator of the apparatus to grasp and manipulate the workpieces; and a blast gun 2t} which is suspended within the interior of the blasting chamber 13. The roof 21 of the blasting chamber 13 is provided with an outlet opening around which is connected an exhaust line 22 which withdraws vapors and dust from the interior of the blasting chamber which occur while the blasting operation is in progress.

As best illustrated in FIG. 2, the aforementioned viewing window 15 is preferably inclined downwardly and in- Wardly and receives a constant spray of wash water on the interior surface thereof to remove dirt and slurry deposits from the window and to better enable the operator to view the blasting operation. The spray of wash Water is received on the viewing window 15 from spray nozzles 23 width are positioned at several closely spaced locations across the breadth of the window and disposed toward the window. Valved water lines 24 and 25 are connected to the spray nozzles 23 and pipe the wash water thereto from a suitable Water supply line, not illustrated. As the water runs down the inclined viewing window 15 it is trapped in a horizontal trough 26 disposed lengthwise along the lower margin of the viewing window. A receiving lip 27 on the edge of the trough 26 in contact with the window directs the wash water into the trough. The trough 26 feeds to a drain pipe 28 which u in turn disposes of the wash water in a suitably located drain, not illustrated.

The blast gun 20 from which is emitted a pressurized jet of abrasive slurry may be of conventional construction well-known in the art and has inlet ports 29 and 30 leading to the barrel of the gun. Ports 29 and 30 are respectively connected with flexible hoses 32 and 33 which deliver compressed air and slurry to the gun 28 to form the liquid blasting jet. Also, as shown in FIG. 1, the hoses 32 and 33 are connected at their opposite ends to pipes 34- and 35, respectively. Pipe 34, which sup plics slurry to the gun 20, passes through the wall of the cabinet enclosure 10 and leads down to and through the wall of the slurry hopper 14 where it emerges into the interior of the hopper at a location disposed wellbeneath :the surface level of the slurry 36 contained therein, for example, as shown in FIG. 3. The pipe 35 supplying compressed air to'the blast gun 20, likewise, preferably runs through the wall of the cabinet and the passage of compressed air therethrough is controlled by a suitable foot valve 37 conveniently located near the foot of the operator. Although normally closed, the foot valve is constructed to open when the operator presses his foot down upon the spring loaded foot lever 33 which is operatively connected to a lever arm 39 on the valve 37 (FIG. 1) by linkage 40. The foot lever 38 is likewise linked to a lever arm 41 on a switch box 42 which provides a an on-off electrical switch for the motor 43 operating the slurry sump pump 44 which pumps slurry from the hopper 14 through pipe 34 to blast gun 26*. When the foot lever 38 is depressed the lever arm 41 closes the electrical circuit in the switch box 42. Thus, electrical wires 45 and 46 leading from the switch box 42 to the motor 43 actuate the latter when the foot lever 38 is depressed thereby causing slurry to be pumped to the blast gun 2t) concurrently with the admission of compressed air to the gun.

The slurrious abrasive utilized in the blasting operation may be of the conventional types and depends in large measure upon the degree of smoothness desired to be produced on the workpiece. For example a fine mesh silica of about 300 mesh screen size mixed in a water carrier and having a consistency ranging from an extremely fluid or watery slurry to a fluid mud may be employed with varying degrees of success depending upon the quality and texture of finish desired. Commercially available abrasives such as Hydrosil Arkansas Abrasive sold by the Hydrapone Equipment Company or KXX240 Aluminum Oxide sold by the Carborundum Company are suitable in most instances where an extremely fine finish is desired. Obviously many types of fine abrasives may be employed and the invention herein is not intended to be limited to those types of abrasives disclosed.

The exhaust system which draws vapors through the exhaust line 22 from the cabinet enclosure and thereby ventilates and effectively reduces fog in the cabinet enclosure will now be described in detail. During the blasting operation moisture and moist vapors in large part composed of the fine abrasive material and dust are generated in the blasting chamber 13. The exhaust system comprises a motor driven centrifugal air displacement pump 48 or other suitable vacuum pump connected in the exhaust line 22. An exit pipe 50 at the outlet end of the exhaust line 22 discharges the exhausted vapors into the hopper 14 at a location substantially beneath the surface level of the slurry supply 36. A vent line "51 extending from exit pipe 50 between the pump 48 and hopper 14 to the atmosphere or suitable disposal apparatus, not illustrated, is provided with a damper 52 which together with another similar damper 53 located in the exit pipe 50 near the hopper 14 serves to control the amount of exhausted vapors returned to the slurry 36. By manual or other adjustment of the dampers 52 and 53 the exhaust vapors may be in part discharged into 4 the slurry 36 and in part vented or may be entirely vented or discharged into the slurry 36.

The wheeled dolly 11 upon which the workpieces are placed prior to being moved into the cabinet enclosure 10 comprises a horizontal rectangular bed 55 carried upon rotatable wheels 56 disposed at spaced locations along opposite sides of the bed and riding on the tracks 12; a vertical side splash wall 57; and a vertical back plate 58. The back plate 58 is constructed and arranged to form a door for the access opening at 60 in the side of the cabinet enclosure 10 when the dolly is wheeled into the blasting chamber 13 and is provided with a suitable handle 59 for easy manual manipulation of the dolly along the tracks 12. As shown in FIG. 3, when the dolly is wheeled into the cabinet enclosure 10 the back plate 58 contacts and forms a snug fit with the Wall of the cabinet enclosure immediately around the access opening 63. Where desired, a gasket or other suitable sealing material may be employed between the mating surfaces of the back plate 58 and Wall area around the access opening 66. The bed 55 of the dolly 11 is preferably of an open-work or lattice structure and may be constructed of wire mesh 62. Wheel blocks 63 securely mounted on the edge of the bed '55 have rotatable stub shafts 64 journailed therein on bearings which carry the wheels 56.

After the workpieces or material have been blasted with abrasive emitted slurry from the blast gun 20 until the desired surface finish has been obtained, the dolly 11 with the workpieces thereon is wheeled from the cabinet enclosure 10 along the tracks 12 to station A where the workpieces are thoroughly washed or rinsed to remove residual slurry and such other foreign matter as may remain on the surfaces of the workpieces. The washing operation preferably utilizes tap water or other suitable washing medium which is sprayed from an overhead spray gun 66 or other suitable means for directing a stream or spray onto the workpiece. The spray gun 66 is operatively attached to a flexible hose 67 coiled around a retractable roller 68 and connected to a conduit 69 leading to a supply source (not shown) of Wash water or other washing medium. Beneath the tracks 12 and disposed under the spray gun 66 is a catch basin 70 having a drain pipe 71 leading to a separator which is shown as a motor driven centrifuge 72. The centrifuge 72 empties into a drain line 73 and a slurry return line 74. The drain line 73 leads to a suitably disposed drain or waste receptacle and the return line 74 feeds to the hopper 14 beneath the surface level of the slurry 36. The centrifuge 72 functions as a separator and dispels excess wash water which would otherwise dilute the residual slurry washed down from the workpieces. The slurry, on the other hand, drains from the centrifuge and is pumped back to the main slurry supply contained in the hopper 14.

After the workpieces have been thoroughly washed at station A, the dolly 11 is transferred along tracks 12 to station E where a corrosion inhibiter is applied to the washed and finished surfaces of the workpieces. The corrosion inhibiter, which may be any conventional antirust solution, or the like, is sprayed from an overhead spray gun 76 which receives a suitable corrosion inhibiting medium through a flexible hose 77. The hose 77 is coiled around a retractable roller 78 suitably mounted overhead and extends therefrom to a storage tank 79 supported at an elevation substantially above the spraying position and storing a supply of the corrosion inhibiting medium. Beneath the spray gun 76 and the track 12 there is a catch basin 80, similar to the catch basin beneath station A, which traps the excess corrosion inhibiting medium dpaining from the workpieces and passing through the openings in the dolly bed 55. Communicating with the catch basin 80 is a valved drain line 81 in which there is a suitable fluid pump, such as a centrifugal pump 82, which returns the excess corrosion inhibiting medium through the return line 83 to the overhead storage tank 79. j.

During periods of idleness in the use of the slurry blasting apparatus it is quite common for the abrasive constituents of the slurry to precipitate to the bottom of the hopper 14. Accordingly, a compressed air line 84, leading into the lowermost portion of the hopper 14 from a valved feed line '85, affords means for alleviating the sedimentation problem arising from such precipitation. As illustrated, the valved feed line 85 may :also be utilized to supply compressed air to the air line 35 leading to the blast gun 20. Hence, by admitting compressed air into the lowermost portion of the hopper 14 from air line 84 prior to pumping the slurry 36 and operating the blast gun 20, the sediment collected therein will be violently agitated and resuspended within its water carrier.

From the foregoing it will be readily apparent that the exhaust system avoids loss and waste of the slurry by enabling the exhausted vapors and air borne abrasive particles to be returned to the slurry hopper for reuse. Additionally, the arrangement of the exhaust system is such that the exhausted vapors and abrasive particles are discharged under positive pressure into the slurry 36 through an outlet or discharge openingin the hopper 14 at a location well beneath the surface level of the slurry 36. Consequently, the slurry 36 may be maintained in a well agitated and homogeneously mixed condition during the use of the slurry blasting apparatus.

It will also be apparent that the workpieces may be transferred quickly and conveniently into and out of the blasting chamber 13 by the dolly 11. Also, the entire slurry blasting or surface finishing, washing and corrosion inhibiting operations may be performed with little effort by a single operator within a very small working area and with only limited movement of workpieces. The dolly, upon which the workpieces are transferred, in addition to increasing the efficiency of the operation and re ducing the time expended to completely finish, wash and treat the workpieces is constructed to cooperate with the cabinet enclosure Ill and function to close the access opening 6t) in the side of the cabinet enclosure. Thus, the necessity of closing a door to confine the slurry within the blasting chamber 13 during the slurry blasting operation is obviated and the physical movements and operations performed by the operator are reduced. Thus, more time is avail-able for productive efforts on the part of the operator of the apparatus.

Although the present invention has been described in substantial detail in the foregoing description, it is not intended that the invention be limited to such details, or otherwise, than is necessitated by the scope of the appended claims.

Having now described the invention in full detail, I claim:

1. In a slurry blasting apparatus including an enclosed slurry blasting chamber emptying into a slurry storage chamber disposed beneath said blasting chamber, the improvement comprising exhaust means for exhausting said blasting chamber, said exhaust means being provided with an inlet opening leading to said blasting chamber and a discharge opening discharging into said storage chamber, said discharge opening being located substantially beneath the slurry surface level of said storage chamber.

2. The combination defined in claim 1, wherein said blasting chamber defines a wall access opening therein and includes a track traversing said opening and extending into the confines of said blasting chamber, a carrier supported for movements along the length of said track into and out of said blasting chamber, said carrier having a bed portion for supporting workpieces thereon and an upright plate rising from said bed, said plate being shaped to close said access opening and mate with marginal wall surfaces surrounding said access opening when said carrier is moved into said blasting chamber.

3. The combination defined in claim 1, including an inclined viewing window formed in said blasting chamber, means positioned within said blasting chamber for emitting a washing medium against said window, said lastmentioned means including a series of spray nozzles arranged in adjacent relationship along a marginal edge of said window, said spray nozzles being directed axially towards said window and inclined with respect thereto, means for supplying a pressurized washing medium to said spray nozzles, whereby said washing medium is emitted from said spray nozzles at'an incline against and over said window.

4. In a slurry blasting apparatus including an enclosed slurry blasting chamber emptying into a slurry storage chamber disposed beneath said blasting chamber, the improvement comprising an exhaust duct, said exhaust duct being provided with an inlet opening leading to said blasting chamber and a discharge opening discharging into said storage chamber, said discharge opening being located substantially beneath the slurry surface level of said storage chamber, an exhaust pump operatively connected with her through said duct into said storage chamber, Venting means for venting said exhaust duct between said inlet and discharge openings, means for control-ling the extent of venting by said venting means.

5. In a slurry blasting and washing apparatus including an enclosed slurry blasting chamber emptying ino a slurry storage chamber disposed beneath said blasting chamber, the improvement comprising an exhaust duct, said exhaust duct being provided with an inlet opening leading to said blasting chamber and an outlet opening discharging into said storage chamber, said discharge opening being located substantially beneath the slurry surface level of said storage chamber, an exhaust pump operatively connected with said exhaust duct between said inlet and outlet openings, a vent opening provided in said exhaust duct between said exhaust pump and said discharge opening, and damper means for controlling the passage through said vent openmg.

6. In combination, a slurry blasting chamber, a washing station adjacent to and exteriorly of said blasting chamber, a slurry storage chamber disposed beneath said blasting chamber, a track communicating between said blasting chamber and said washing station, carrier means for transferring workpieces in a path along said track from said blasting chamber to said washing station, a slurry blasting gun within said blasting chamber operatively disposed along the path of said carrier, washing means provided at said washing station operatively disposed along the path of said carrier for emitting a washing medium onto said workpieces to remove residual slurry therefrom, a return basin disposed beneath said track at said washing station for receiving said washing medium and residual slurry washed from said workpieces, separator means receiving said washing medium from said return basin for separating said residual slurry from said washing medium and having a slurry return line returning the separate slurry into said slurry storage chamber for reuse.

7. The combination defined in claim 6, wherein said slurry return line leads into said slurry storage chamber at a location substantially beneath the slurry surface level thereof.

8. In combination, a slurry blasting chamber, a washing station, a corrosion inhibiting station, said washing and corrosion inhibiting stations being successively adjacent to said blasting chamber and located exteriorly thereof, a track communicating between said blasting chamber, said washing station and said corrosion inhibiting station, carrier means for transferring workpieces along said track from said blasting chamber to both of said stations, a slurry blasting gun within said blasting chamber and operatively disposed along the path of said carrier, washing means provided at said washing station operatively disposed along the path of said carrier, means for emitting a corrosion inhibiter across the path of said carrier at said corrosion inhibiting station, a return basin at said corrosion inhibiting station disposed beneath the path of 7 said carrier to receive the emissions from the last-mentioned means, a storage tank for holding a supply of corrosion inhibiter, said storage tank being provided with a discharge opening feeding into said corrosion inhibiter emitting means, and said return basin being provided with an outlet opening emptying into said storage tank.

9. In combination, a slurry blasting chamber defining a wall access opening for receiving therein workpieces which are to be blasted, a washing station adjacent to said blasting chamber for washing said workpieces after removal from said blasting chamber, a dolly track passing through said access opening into the interior confines of said blasting chamber and extending between said blasting chamber and said washing station, a dolly carried on said track, said dolly being movable along said track between the interior confines of said blasting chamber and said washing station and having a bed for carrying Workpicces thereon, slurry blasting means within said blasting chamber, said slurry blasting means being operatively disposed along the path of said track and within blasting range of said bed when said dolly is positioned within said blasting chamber, and washing means at said Washing station operatively disposed along the path of said tracks for washing workpieces carried on said bed.

10. In combination, a slurry storage chamber, an enclosed slurry blasting chamber emptying into said storage chamber, a washing station adjacent to said blasting chamber, blasting means within said blasting chamber for blasting a workpiece with an abrasive slurry, carrier means for supporting said workpiece within said blasting chamber and for transferring said workpiece therefrom to said washing station, means for washing said workpiece to remove residual abrasive slurry adhering to the surfaces thereof, means for trapping the washings removed from said workpiece, means for separating the abrasives from said washings and returning said abrasives to said slurry storage chamber for reuse.

11. The combination defined in claim 10, wherein said washing means comprises a spray head, a flexible hose connecting said spray head to a supply of washing medium,

8 and retractable means carrying said hose in a position overlying said washing station.

12. The combination defined in claim 10, wherein said blasting chamber defines a wall access opening for receiving said carrier means within said blasting chamber, and wherein said carrier means includes an upright plate shaped to close said access opening and mate with marginal wall surfaces surrounding said access opening when said carrier is moved into said blasting chamber.

13. In combination, a slurry storage chamber, an enclosed slurry blasting chamber emptying into said storage chamber, exhaust means for exhausting said blasting chamber, said exhaust means being provided with an inlet opening leading to said blasting chamber and a discharge opening discharging into said storage chamber, said dischange opening being located substantially beneath the slurry surface level of said storage chamber, a Washing station adjacent to said blasting chamber, carrier means for supporting said workpiece within said blasting chamber and for transferring said workpiece therefrom to said washing station, means for washing said workpiece to remove residual abrasive slurry adhering to the surfaces thereof, means for trapping the washings removed from said workpiece, means for separating the abrasives from said washings and returning said abrasives to said slurry storage chamber for reuse.

References Cited in the file of this patent UNITED STATES PATENTS 1,643,175 Rich Sept. 20, 1927 2,576,008 Gladfelter et al Nov. 20, 1951 2,627,149 MacCracken Feb. 3, 1953 2,753,664 Garver July 10, 1956 2,763,964 Luce Sept. 25, 1956 2,815,716 Ransohoif Dec. 10, 1957 2,876,601 McFadden Mar. 10, 1959 FOREIGN PATENTS 612,200 Great Britain Nov. 9, 1948 

1. IN A SLURRY BLASTING APPARATUS INCLUDING AN ENCLOSED SLURRY BLASTING CHAMBER EMPTYING INTO A SLURRY STORAGE CHAMBER DISPOSED BENEATH SAID BLASTING CHAMBER, THE IMPROVEMENT COMPRISING EXHAUST MEANS FOR EXHAUSTING SAID BLASTING CHAMBER, SAID EXHAUST MEANS BEING PROVIDED WITH AN INLET OPENING LEADING TO SAID BLASTING CHAMBER AND A DISCHARGE OPENING DISCHARGING INTO SAID STORAGE CHAMBER, SAID DISCHARGE OPENING BEING LOCATED SUBSTANTIALLY BENEATH THE SLURRY SURFACE LEVEL OF SAID STORAGE CHAMBER. 